CN113767522A

CN113767522A - Method and apparatus for reducing passive intermodulation distortion in a transmission line

Info

Publication number: CN113767522A
Application number: CN202080031718.0A
Authority: CN
Inventors: F·奥德拉塞克; T·特尔; J·卡西克
Original assignee: Commscope Technologies LLC
Current assignee: Commscope Technologies LLC
Priority date: 2019-05-02
Filing date: 2020-03-05
Publication date: 2021-12-07
Also published as: WO2020222911A1; US20200350652A1

Abstract

Methods and apparatus for reducing passive intermodulation distortion generated by a splice attachment conductor by forming a splice with a single metal or covering the splice with a layer of a single metal having a thickness greater than the skin depth of the frequency of a signal propagating through the splice.

Description

Method and apparatus for reducing passive intermodulation distortion in a transmission line

Cross Reference to Related Applications

This application claims the benefit of U.S. patent application serial No. 62/842,363 filed on 5/2/2019; the foregoing patent application is incorporated by reference herein in its entirety as if fully set forth.

Background

A communication system includes at least one duplexer and/or filter coupled to one or more antennas. Each duplexer or filter may be coupled to an antenna by a transmission line system, e.g., using a trunk branch architecture. Some of the transmission lines of the transmission line system may also be referred to as phasing lines. The length of the phasing line or lines can be designed to impedance match the duplexer or filter in the passband.

To reduce insertion loss, transmission lines may be formed within a conductive block, such as a metal block. Due to the complex structure of the transmission line, the conductive block may be formed of at least two conductive parts which are subsequently attached, e.g. by soldering or welding and/or mechanical fasteners, such as screws.

Although different types of transmission lines may be implemented in the conductive block, one type of transmission line that may be used is a coaxial waveguide. The coaxial waveguide includes a center conductor surrounded by an insulator; the conductive block forms an outer conductor surrounding the insulator and thus the center conductor. When coaxial waveguides are used to form transmission lines having trunk and branch architectures, one or more coaxial branch transmission lines may have to be coupled to a coaxial trunk transmission line. This may require connecting the center conductor of the phasing or spur transmission line to the center conductor of the main transmission line.

Typically, the center conductors of the trunk and branch transmission lines are electrically and mechanically connected by a joint (e.g., a solder joint). The soldered joints typically include different conductors. For example, the solder joints may be formed from a metal alloy (e.g., lead-tin). Due to the use of different conductors, oxides are formed on the conductors when forming the solder joints and/or the irregular surface quality of the solder joints, passive intermodulation distortion (PIMD) products may be generated.

Passive intermodulation distortion (PIMD) as well as active intermodulation distortion, produces a hybrid product. The mixing product or PIMD product may reduce the sensitivity of the receiver of the communication system and thus reduce the reception range of the communication system.

Disclosure of Invention

A method is provided for splicing a first conductor of a first transmission line to a second conductor of a second transmission line. The method comprises the following steps: attaching the first conductor to the second conductor with a joint formed from at least one other conductor, wherein the at least one other conductor comprises one or more types of metals; and if the at least one other conductor comprises at least one of more than one metal and a mechanical fastener, the method further comprises covering at least the joint with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

Drawings

Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered to be limiting of scope, the exemplary embodiments will be described with additional specificity and detail through use of the accompanying drawings, in which:

FIG. 1A illustrates a block diagram of one embodiment of a wireless communication device made in accordance with one embodiment of the present invention;

FIG. 1B illustrates an embodiment of a remote antenna unit made in accordance with an embodiment of the present invention;

FIG. 2 illustrates a block diagram of one embodiment of a distributed antenna system implemented according to one embodiment of the invention;

FIG. 3A illustrates a cross-section of one embodiment of a portion of a transmission line system formed in accordance with one embodiment of the present invention;

FIG. 3B shows a diagram of two conductors connected by a joint covered with a single type of metal; and

fig. 4 shows a flow diagram of one embodiment of making linkers that result in a reduction in PIMD product.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments. It is to be understood, however, that other embodiments may be utilized and structural, mechanical and electrical changes may be made. Moreover, the methods set forth in the drawings and the description should not be construed as limiting the order in which the various steps may be performed. The following detailed description is, therefore, not to be taken in a limiting sense.

The techniques described below are applicable to any type of communication system configured to operate in one or more frequency bands, for example a cellular base station, such as an LTE eNodeB used in a cellular network, or a repeater device (e.g., a remote antenna unit of a Distributed Antenna System (DAS) or a single node repeater). However, for instructional reasons, the description of some embodiments is presented below generally in connection with wireless communication devices, and in particular, in connection with remote antenna units of a DAS. It should be understood, however, that the techniques described herein may be used with wireless communication devices other than remote antenna units.

Fig. 1A illustrates a block diagram of one embodiment of a wireless communication device 100A made in accordance with one embodiment of the present invention. Wireless communication device 100A may comprise any communication device employing one or more filter units. Examples of wireless communication devices 100 include, for example, cellular base stations (e.g., LTE enodebs used in cellular networks) and repeater devices (e.g., remote antenna units of DAS or single node repeaters). In the illustrated embodiment, the wireless communication device 100 is configured to facilitate wireless communication with at least one other wireless communication device 108 (e.g., User Equipment (UE)) via at least one signal path.

The wireless communication device 100 includes

N signal paths

110A, 110B, 110N. Each

signal path

110A, 110B, 110N includes a respective

main portion

102A, 102B, 102N coupled to a

respective filter cell

104A, 104B, 104N. For teaching purposes, three signal paths are shown in fig. 1A and B; however, N may be an integer greater than or equal to one.

Each

signal path

110A, 110B, 110N includes at least one of an uplink signal path and a downlink signal path. The downlink signal path is configured to output one or more downlink radio frequency signals transmitted from one or more antennas 106 associated with the wireless communication device 100 for reception by at least one other wireless communication device 108. The uplink signal path 104 is configured to receive one or more uplink radio frequency signals transmitted from at least one wireless communication device 108. For example, where the wireless communication device 100 is embodied as a base station or access point, the downlink and uplink signal paths are configured to perform all layer-3, layer-2, and layer-1 processing and operations, respectively, necessary for generating and transmitting downlink radio frequency signals and receiving, demodulating, and decoding uplink radio frequency signals, required for the relevant wireless interface.

In other embodiments where the wireless communication device 100 is implemented as a repeater device (e.g., a remote antenna unit or a single node repeater of a DAS), the downlink signal path and the uplink signal path are respectively configured to perform at least some of the repeater processing or operations necessary to output the downlink radio frequency signals as repeated versions of the downlink radio frequency signals originally transmitted by one or more other base stations or access points, and to receive the uplink radio frequency signals and output repeated versions of the uplink radio frequency signals transmitted to one or more base stations or access points. As used herein, "downlink" refers to the direction of signal flow toward the antenna 106 and other wireless communication devices 108, while "uplink" refers to the direction of signal flow from the antenna 106 and other wireless communication devices 108.

Each

filter unit

104A, 104B, 104N comprises one or more filters, e.g. band pass filters. Alternatively, the filter unit may be an n-multiplexer (n-plexer). The n multiplexer comprises n filters with unique non-overlapping three decibel passbands; n is an integer greater than or equal to two. For example, n may be two and the filter unit will be a duplexer. For an n-multiplexer (e.g., a duplexer), each major portion of the uplink path and each major portion of the downlink path are coupled to a unique filter of the n-multiplexer. Thus, the n-multiplexer provides isolation between such paths.

Typically, for a duplexer, a major portion of the uplink path and a major portion of the corresponding downlink path are coupled to the only filters of the duplexer. Thus, the duplexer provides isolation between the main portion of the uplink path and the main portion of the downlink path.

The transmission line system 105 couples at least one antenna 106 to each

filter unit

104A, 104B, 104N. Each of the at least one antenna 106 and the transmission line system 105 may or may not be part of the wireless communication device 100A. Each

second portion

112A, 112B, 112N of each

signal path

110A, 110B, 110N comprises a

corresponding filter cell

104A, 104B, 104N. Each

second portion

112A, 112B, 112N also includes a corresponding portion of the transmission line system 105 and/or at least one antenna 106, provided these components are part of the wireless communication device 100A.

The transmission line system 105 shown includes a transmission line trunk 101 including transmission

line trunk segments

101A, 101B, 101N coupled to one another in sequence. Phasing

lines

107A, 107B, 107C connect the transmission line trunk 101 to

corresponding filter units

104A, 104B, 104N at

connection nodes

107A, 107B, 107N. Each phasing line is connected in parallel with other phasing lines to the transmission line trunk 101; each phasing line may be connected to a connection between two unique transmission line trunk segments.

Fig. 1B illustrates an embodiment of a Remote Antenna Unit (RAU)100B made in accordance with an embodiment of the present invention. Remote antenna unit 100B is similar to wireless communication device 100A, but includes N downlink signal paths 110A-D, 110B-D, 110N-D and N uplink signal paths 110A-U, 110B-U, 110N-U. The uplink and downlink signal paths operate as described above for wireless communication device 100A.

Further, in remote antenna unit 100B, each downlink signal path 110A-D, 110B-D, 110N-D includes a corresponding main portion 102A-D, 102B-D, 102N-D coupled to a corresponding duplexer 104A ', 104B ', 104N '. The main portion of the downlink signal path may also be referred to as the primary downlink signal path. The main portion of the uplink signal path may also be referred to as the primary uplink signal path.

Each duplexer is configured such that it includes at least a portion of either (or both) of a downlink signal path and an uplink signal path. The portions of the downlink and uplink signal paths are the main portions of the downlink and uplink signal paths discussed above. The portions of the downlink and uplink signal paths (if any) included in each duplexer are referred to herein as "second portions" of the downlink and uplink signal paths. The second portions of the downlink signal paths 112A-D, 112B-D, 112N-D may also be referred to as second downlink signal paths. The second portions of the uplink signal paths 112A-U, 112B-U, 112N-U may also be referred to as second uplink signal paths.

As with the wireless communication device 100A, each of the at least one antenna 106 and the transmission line system 105 may or may not be part of the remote antenna unit 100B. Thus, the

second portions

112A, 112B, 112N may also be located in corresponding portions and/or antennas of the transmission line system 105, depending on whether those components are part of the remote antenna unit 100B.

Fig. 2 illustrates a block diagram of one embodiment of a distributed antenna system 200 implemented according to one embodiment of the invention. The DAS 200 includes one or more master units 202 communicatively coupled to one or more RAUs 204 via one or more cables 209 (e.g., optical or copper cables). Each remote antenna unit 204 may be directly communicatively coupled to one or more master units 202 or indirectly communicatively coupled to the one or more master units via one or more other remote antenna units 204 and/or via one or more extension (or other intermediate) units 208. Each RAU204 is configured to use one of the implementations in the embodiments described below.

Further, each RAU204 is configured to be coupled to one or more antennas 206. However, in alternative embodiments, the RAU may include one or more antennas.

The DAS 200 is coupled to one or more base stations 203 and is configured to improve the wireless coverage provided by the base stations 203. The capacity of each base station 203 may be dedicated to the DAS 200 or may be shared among the DAS 200 and a base station antenna system co-located with the base station 203 and/or one or more other repeater systems.

In the embodiment shown in fig. 2, the capacity of one or more base stations 203 is dedicated to DAS 200 and co-located with DAS 200. Base stations 203 are coupled to DAS 200. However, it is to be understood that other embodiments may be practiced in other ways. For example, the capacity of one or more base stations 203 can be shared with the DAS 200 and base station antenna systems co-located with the base stations 203 (e.g., using donor antennas). Base station 203 may include one or more base stations for providing commercial cellular wireless services and/or one or more base stations for providing public and/or private security wireless services, such as wireless communications for emergency services organizations (e.g., police, fire, and emergency medical services) to prevent or counter accidents that harm or harm personnel or property.

The base station 203 may be coupled to the main unit 202 using a network of attenuators, combiners, splitters, amplifiers, filters, cross-connects, etc. (sometimes collectively referred to as "interface points" or "POIs"). This network may be included in the master unit 202 and/or may be separate from the master unit 202. This is done so that in the downlink, a desired set of RF channels output by the base stations 203 can be extracted, combined and routed to the appropriate master unit 202, and upstream, a desired set of carriers output by the master unit 202 can be extracted, combined and routed to the appropriate interface of each base station 203. However, it should be understood that this is one example, and other embodiments may be implemented in other ways.

In general, each master unit 202 includes a downlink signal path 210 configured to receive one or more downlink signals from one or more base stations 203. Each base station downlink signal includes one or more radio frequency channels for communicating in the downlink direction with user equipment 214 over an associated wireless air interface. Typically, each base station downlink signal is received as an analog radio frequency signal, but in some embodiments, one or more base station signals are received in digital form (e.g., in digital baseband form conforming to the common public radio interface ("CPRI") protocol, the open radio equipment interface ("ORI") protocol, the open base station standard plan ("OBSAI") protocol, or other protocol). The downlink signal path 210 in each master unit 202 is further configured to generate one or more downlink transmission signals derived from one or more base station downlink signals and transmit the one or more downlink transmission signals to one or more remote antenna units 204.

Each RAU204 is configured to receive downlink transmission signals transmitted thereto from one or more master units 202 and to use the received downlink transmission signals to generate one or more downlink radio frequency signals that are transmitted from one or more antennas associated with that remote antenna unit 204 for reception by user equipment 214. In this way, the DAS 200 increases the coverage area of the downlink capacity provided by the base station 203.

Further, each RAU204 is configured to receive one or more uplink radio frequency signals transmitted from user equipment 214. These signals are analog radio frequency signals.

Each RAU204 is further configured to generate one or more uplink transmission signals derived from one or more remote uplink radio frequency signals and transmit the one or more uplink transmission signals to one or more master units 202.

Each master unit 202 includes an uplink signal path 216 configured to receive respective uplink transmission signals transmitted thereto from one or more RAUs 204 and to use the received uplink transmission signals to generate one or more base station uplink radio frequency signals provided to one or more base stations 203 associated with the master unit 202. In general, this involves, among other things, combining or summarizing the uplink signals received from multiple RAUs 204 to produce a base station signal provided to each base station 203. In this way, the DAS 200 increases the coverage area of the uplink capacity provided by the base station 203.

Each expansion unit 208 includes a downlink signal path 218 configured to receive downlink transmission signals transmitted thereto from the master unit 202 (or another expansion unit 208) and to transmit the downlink transmission signals to one or more RAUs 204 or other downstream expansion units 208. Each expansion unit 208 also includes an uplink signal path 220 configured to receive respective uplink transmission signals transmitted thereto from one or more RAUs 204 or other downstream expansion units 208, combine or sum the received uplink transmission signals, and transmit the combined uplink transmission signals upstream to the main unit 202 or another expansion unit 208. In other embodiments, one or more remote antenna units 204 are coupled to one or more main units 202 via one or more other remote antenna units 204 (e.g., where the remote antenna units 204 are coupled together in a daisy chain or ring topology).

The

downlink signal paths

210, 218 and

uplink signal paths

216, 220 in each of the main unit 202 and the expansion unit 208, respectively, may be implemented using suitable circuitry. Thus, the

downlink signal paths

210, 218 may also be referred to as "downlink circuits" or "downlink DAS circuits" 210, 218, respectively, and the

uplink signal paths

216, 220 may also be referred to as "uplink circuits" or "uplink DAS circuits" 216, 220, respectively. The

downlink signal paths

210, 218 and

uplink signal paths

216, 220 may include one or more of the following: suitable connectors, attenuators, combiners, splitters, amplifiers, filters, duplexers, transmit/receive switches, analog-to-digital converters, digital-to-analog converters, electrical-to-optical converters, optical-to-electrical converters, mixers, Field Programmable Gate Arrays (FPGAs), microprocessors, transceivers, framers, etc., to implement the above features. In addition, respective downlink and uplink signal paths in each of the main unit 202 and the extension unit 208 may share common circuitry and/or components.

The DAS 200 may use digital transmission, analog transmission, or a combination of digital and analog transmission to generate and transmit transmission signals between the main unit 202, the remote antenna units 204, and any expansion units 208. Each of the main unit 202 and the extension unit 208 in the DAS 200 also includes a respective Controller (CNTRL)212 (or controller circuit). The controller 212 is implemented using one or more programmable processors executing software configured to implement various control functions.

Returning to fig. 1A and 1B, an implementation of the transmission line system 105 according to an embodiment of the present invention will now be described. The transmission line system 105 may be formed from one or more different types of transmission lines including, but not limited to, coaxial waveguides, rectangular waveguides, circular waveguides, microstrips, and striplines. Embodiments of the present invention may be used for splices that join or cover the conductors (including ground planes) of a transmission line. Embodiments of the present invention may be used to implement the transmission line system 105 described above or transmission lines for other applications.

For instructional reasons, the transmission line system 105 will be described. Further, for instructional reasons, the transmission line system 105 will be shown as implemented with a coaxial waveguide. Coaxial waveguides include a center conductor surrounded by an insulator, which may include, for example, a gas and/or solid insulator material. The outer conductor surrounds the insulator and thus the center conductor.

The insulator may be composed of one or more phases of material (e.g., gaseous and/or solid material). If a gas insulator is used, the insulator may be, for example, air or nitrogen. Alternatively, if a gaseous insulator is used, one or more pieces of solid insulator may also be used to support the center conductor and ensure that the center conductor does not contact the outer conductor. The center conductor may be formed as a rod or wire from a conductor such as brass, copper, aluminum, and/or stainless steel.

The outer conductor may be formed of one or more conductive portions. For example, each of the two conductive portions may be machined to form the outer conductor. The center conductor and the insulator are disposed in the two conductive portions. The inner conductor may be secured within the two conductive portions by one or more pieces of solid insulation. Pieces of solid insulation may be disposed in openings within the outer conductor, which are typically filled with gaseous insulation. Then, two conductive portions may be attached according to one embodiment of the present invention.

Fig. 3A illustrates a cross-section of one embodiment of a portion of a transmission line system 305 formed in accordance with one embodiment of the present invention. The illustrated portion of the transmission line system 305 includes a first transmission line trunk segment 301A, a second transmission line trunk segment 301B, and a phasing line 307 formed with the coaxial transmission line. The first transmission line trunk segment 301A includes a first trunk center conductor 332A, a first trunk insulator 334A, and a first trunk outer conductor formed from a first conductor 330A and a second conductor 330B. The second transmission line trunk segment 301B includes a second trunk center conductor 332B, a second trunk insulator 334B, and a second trunk outer conductor formed from a first conductor 330A and a second conductor 330B. The phasing line 307 includes a phasing line center conductor 332C, a phasing line insulator 334C, and a phasing line outer conductor formed by a first conductor 3301 and a second conductor 330B.

The first and second

trunk center conductors

332A, 332B may or may not be formed from a single wire or a single rod. The first trunk insulator 334A, the second trunk insulator 334B, and/or the phasing insulator 334C may or may not be formed from a single insulator, such as air. As described above, each of the first trunk insulator 334A, the second trunk insulator 334A, and the phase line insulator 334B may be formed of a gaseous insulator and/or pieces of solid insulator.

Optionally, first conductor 330A and/or second conductor 330B may have material removed, e.g., by machining, laser ablation, etc., to facilitate insertion of an insulator in place of the removed material. Alternatively, the region where the insulator is placed may be formed by casting instead of the removed material. In the illustrated embodiment, the cross-section of the region in each of the first conductor 330A and the second conductor 330B where the insulator is placed is semicircular; however, other cross-sections may be used, such as U-shaped and semi-elliptical.

If the first trunk insulator 332A, the second trunk insulator 334B, and the phase line insulator 334C are implemented with gaseous insulators, solid insulators may be periodically or non-periodically disposed instead of the gaseous insulators to support the

center conductors

332A, 332B, 332C so that they do not contact the outer conductors. Each piece of solid insulator may insulate all or a portion of the circumference of a portion of the conductor with which it contacts; the portion of the circumference not insulated by a piece of solid insulation will be insulated by gaseous insulation.

Typically, the center conductor of the phasing line must be electrically and mechanically joined to the trunk line. This may be performed before or after the conductor is inserted into the outer conductor (e.g., the first conductive portion 330A and the second conductive portion 330B). The resulting joint 336 is achieved by welding, brazing, soldering, and/or any other means of mechanically attaching two conductors, including, for example, using an adhesive (e.g., epoxy or glue) and/or mechanical fasteners (e.g., screws and nuts and bolts); welding, soldering, welding and/or any other means of mechanically attaching two conductors is hereinafter collectively referred to as joining. If a conductive material is not used to engage the conductors, the joint 336 and a portion of each conductor may be covered with a conductive material (e.g., as described further herein) to enable an electrical connection between the conductors.

Conventionally made linkers produce undesirable PIMD products. PIMD products can be reduced in at least two ways. First, the center conductor is first bonded using conventional techniques. A single type of metal (or metal layer) such as silver, gold or copper is then deposited on the joint (and possibly also on the central conductor), for example by electroplating and/or sputtering. Sputtering is a form of physical vapor deposition that involves ejecting material from a target onto other materials, such as a joint. Electroplating is described further below.

The thickness of the single type of metal deposited on at least the joint should be at least one skin depth of the carrier frequency of the signal that the transmission line system 105 is configured to propagate. The alternating current penetrates substantially only one skin depth of the carrier frequency of such signals from the external conductive surface. The skin depth varies with the material properties and carrier frequency. In one embodiment, the thickness of the single type of metal deposited should be ten microns; however, other thicknesses may be used depending on the material characteristics and the frequency at which the transmission line is used.

An exemplary method of silver plating will be shown. Silver plating can be performed using an electrolytic cell comprising silver nitrate and potassium cyanide. The anode of the cell is coupled to a piece of silver placed in an electrolytic cell. The cathode of the battery is coupled to the bonded center conductor; the joined center conductor (with or without one of the first conductive portion 330A and the second conductive portion 330B) is placed in the electrolytic cell. The plating time depends on the desired plating thickness, the area to be plated and the battery volt ampere. Electroplating may be used to deposit a layer of another single type of metal (e.g., gold or copper); however, the cell material and/or the metal in which the cell is placed will be different.

Fig. 3B shows a diagram of two conductors connected by a joint covered with a single type of metal 300B. First conductor 331A is connected to second conductor 332B by joint 336. The first conductor 331A and the second conductor 332B may be the center conductors of coaxial waveguides, e.g., the trunk center conductor and the phase line center conductor. Contact 336, first conductor 331A, and second conductor 332B are covered by a conductive layer 337 (e.g., silver).

Instead of plating the joint, the joint may be formed of the above-described materials, such as metals or metal alloys (including, for example, silver, gold, or copper), to form the joint by soldering, brazing, welding, or other methods of conductively joining conductors. Thus, for example, a weld comprising a single metal type or a braze or filler comprising a single metal type is used to form a joint, such as joint 336. Optionally, the joint formed from a single type of metal has a diameter or thickness (e.g., at least ten microns) at least equal to one skin depth of the carrier frequency of the signal that the transmission line system 105 is configured to propagate. If the single type of metal is silver and brazing is used to form the joint, a silver brazing compound, such as EcoBraz 38255B, is formed with a flux (such as FP 6000) at temperatures between 550C and 600C. Heat may be applied during the brazing process using a cautery.

Fig. 4 shows a flow diagram of one embodiment of making linkers that result in a reduced PIMD product 400. To the extent that the embodiment of method 400 shown in fig. 4 is described herein as being implemented in the systems and devices described with respect to fig. 1-3B, it should be understood that other embodiments may be implemented in other ways. For ease of explanation, the blocks of the flow chart have been arranged in a substantially sequential manner; however, it is to be understood that such an arrangement is merely exemplary, and that the processes associated with the methods (and the blocks shown in the figures) may occur in a different order (e.g., where at least some of the processes associated with the blocks are performed in parallel and/or in an event-driven manner).

In block 440, the first conductor is attached to the second conductor with a joint formed from at least one other conductor, wherein the at least one other conductor includes one or more types of metals. Optionally, the at least one conductor comprises only one type of metal, for example silver. Optionally, the attachment including at least one attachment includes at least one of a weld, a braze, a weld, an adhesive, and a mechanical fastener.

Optionally, in block 442, if the at least one other conductor includes at least one of more than one metal and a mechanical fastener, at least the joint is covered with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of the signal, wherein the transmission line is configured to propagate the signal. Optionally, if the at least one other conductor comprises at least one of more than one metal, an adhesive, and a mechanical fastener, covering at least the joint with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of the signal, wherein the transmission line is configured to propagate the signal. Optionally, the one metal is silver.

Optionally, in block 444, the first conductor and the second conductor are inserted into at least one conductive portion that forms at least a portion of an outer conductor of the coaxial transmission line. Optionally, in block 446, at least one solid insulator is interposed between the at least one conductive portion and at least one of the first conductor and the second conductor. Optionally, in block 448, at least one other conductive portion is attached to the at least one conductive portion to form an outer conductor.

Exemplary embodiments

Example 1 includes a method for splicing a first conductor of a first transmission line to a second conductor of a second transmission line, the method comprising: attaching the first conductor to the second conductor with a joint formed from at least one other conductor, wherein the at least one other conductor comprises one or more types of metals; and if the at least one other conductor comprises at least one of more than one metal and a mechanical fastener, the method further comprises covering at least the joint with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

Example 2 includes the method of example 1, wherein if the at least one other conductor includes more than at least one of the one metal, an adhesive, and the mechanical fastener, the method further comprises covering at least the joint with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

Example 3 includes the method of any one of examples 1-2, wherein the at least one other conductor includes only one type of metal that is silver.

Example 4 includes the method of any one of examples 1-3, wherein the one type of metal used to form the layer is silver.

Example 5 includes the method of any of examples 1-4, wherein attaching includes at least one of welding, brazing, and soldering.

Example 6 includes the method of any of examples 1-5, wherein the covering includes at least one of electroplating and sputtering.

Example 7 includes the method of any one of examples 1-6, wherein the first conductor and the second conductor are each a center conductor of a coaxial transmission line.

Example 8 includes the method of example 7, further comprising inserting the first conductor and the second conductor into at least one conductive portion forming at least a portion of an outer conductor of the coaxial transmission line.

Example 9 includes the method of any one of examples 7-8, further comprising inserting at least one solid insulator between the at least one conductive portion and at least one of the first conductor and the second conductor.

Example 10 includes the method of example 9, attaching at least one other conductive portion to the at least one conductive portion to form the outer conductor.

Example 11 includes a transmission line system, comprising: a transmission line trunk connected to at least one phasing line; wherein the conductor of each phasing line is connected to the conductor of the transmission line trunk by a junction formed by at least one conductor, wherein the at least one conductor comprises one or more metals; and if the at least one other conductor comprises more than one metal, covering at least the joint with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line system is configured to propagate the signal.

Example 12 includes the transmission line system of example 11, wherein if the at least one other conductor includes more than at least one of the one metal, an adhesive, and the mechanical fastener, at least the joint is covered with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

Example 13 includes the transmission line system of any one of examples 11-12, wherein the at least one other conductor includes only one metal that is silver.

Example 14 includes the transmission line system of any one of examples 11-13, wherein the one metal used to form the layer is silver.

Example 15 includes the transmission line system of any of examples 11-14, wherein the transmission line trunk is configured to be coupled to at least one antenna; and wherein each phasing line is configured to be coupled to a filter unit.

Example 16 includes the transmission line system of any of examples 11-15, wherein the joint comprises one of a welded joint, a brazed joint, a welded joint, an adhesive joint, and a mechanical fastener joint.

Example 17 includes the transmission line system of any one of examples 11-16, wherein the conductor of the phasing line and the conductor of the transmission line trunk are each a center conductor of a coaxial transmission line.

Example 18 includes the transmission line system of example 17, further comprising at least one conductive portion forming an outer conductor of the coaxial transmission line.

Example 19 includes the transmission line system of example 18, further comprising at least one solid insulator interposed between the at least one conductive portion and at least one of the conductor of each phasing line and the conductor of the trunk transmission line.

Example 20 includes the transmission line system of any of examples 18-19, further comprising at least one other conductive portion attached to the at least one conductive portion to form the outer conductor.

Example 21 includes a remote antenna unit, comprising: a first primary uplink signal path; a first primary downlink signal path; an nth primary uplink signal path, where N is an integer greater than or equal to two; an nth primary downlink signal path; a first duplexer coupled to the first primary uplink signal path and the first primary downlink signal path; an Nth duplexer coupled to the Nth primary uplink signal path and the Nth primary downlink signal path; wherein the first duplexer and the Nth duplexer are configured to be coupled to a transmission line system; wherein the transmission line system includes a transmission line trunk connected to the first phasing line and the Nth phasing line; wherein the conductor of each phasing line is connected to the conductor of the transmission line trunk by a junction formed by at least one conductor, wherein the at least one conductor comprises one or more metals; and if the at least one other conductor comprises more than one metal, the method further comprises covering at least the joint with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line system is configured to propagate the signal; and wherein the transmission line system is configured to couple an antenna to the first duplexer and the Nth duplexer.

Example 22 includes the remote antenna unit of example 21, wherein if the at least one other conductor includes at least one of more than the one metal, an adhesive, and the mechanical fastener, at least the joint is covered with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

Example 23 includes the remote antenna unit of any of examples 21-22, wherein the at least one other conductor includes only one metal that is silver.

Example 24 includes the remote antenna unit of any of examples 21-23, wherein the one metal used to form the layer is silver.

Example 25 includes the remote antenna unit of any of examples 21-24, wherein the transmission line trunk is configured to be coupled to the at least one antenna; and wherein each phasing line is configured to be coupled to a unique diplexer.

Example 26 includes the remote antenna unit of any of examples 21-25, wherein the joint comprises one of a solder joint, a soldered joint, and a welded joint.

Example 27 includes the remote antenna unit of any of examples 21-26, wherein the conductor of the phasing line and the conductor of the transmission line trunk are each a center conductor of a coaxial transmission line.

Example 28 includes the remote antenna unit of example 27, further comprising at least one conductive portion forming an outer conductor of the coaxial transmission line.

Example 29 includes the remote antenna unit of example 28, further comprising at least one solid insulator interposed between the at least one conductive portion and at least one of the conductor of each phasing line and the conductor of the trunk transmission line.

Example 30 includes the remote antenna unit of any of examples 21-29, further comprising the transmission line system.

Example 31 includes the remote antenna unit of example 30, further comprising the antenna.

The terms "about" or "substantially" indicate that the specified value or parameter may be changed slightly, as long as the change does not result in a process or structure inconsistent with the illustrated embodiments. Finally, the "exemplary" indication description is used as an example, and not to imply that it is ideal.

Various embodiments of the invention defined by the appended claims have been described. Nevertheless, it will be understood that various modifications to the described embodiments may be made without departing from the spirit and scope of the claimed invention. Accordingly, other embodiments are within the scope of the following claims. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Claims

1. The following are exemplary claims. The claims are not intended to be exhaustive or limiting. The applicant reserves the right to introduce additional claims directed to the subject matter granted to this application.

A method for splicing a first conductor of a first transmission line to a second conductor of a second transmission line, comprising:

attaching the first conductor to the second conductor with a joint formed from at least one other conductor, wherein the at least one other conductor comprises one or more types of metals; and is

If the at least one other conductor comprises at least one of more than one metal and a mechanical fastener, the method further comprises covering at least the joint with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

2. The method of claim 1, wherein if the at least one other conductor comprises at least one of more than the one metal, an adhesive, and the mechanical fastener, the method further comprises covering at least the joint with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

3. The method of claim 1, wherein the at least one other conductor comprises only one type of metal that is silver.

4. The method of claim 1, wherein the one type of metal used to form the layer is silver.

5. The method of claim 1, wherein attaching comprises at least one of welding, brazing, and soldering.

6. The method of claim 1, wherein covering comprises at least one of electroplating and sputtering.

7. The method of claim 1, wherein the first conductor and the second conductor are each a center conductor of a coaxial transmission line.

8. The method of claim 7, further comprising inserting the first conductor and the second conductor into at least one conductive portion forming at least a portion of an outer conductor of the coaxial transmission line.

9. The method of claim 7, further comprising inserting at least one solid insulator between the at least one conductive portion and at least one of the first conductor and the second conductor.

10. The method of claim 9, attaching at least one other conductive portion to the at least one conductive portion to form the outer conductor.

11. A transmission line system comprising:

a transmission line trunk connected to at least one phasing line;

wherein the conductor of each phasing line is connected to the conductor of the transmission line trunk by a junction formed by at least one conductor, wherein the at least one conductor comprises one or more metals; and is

If the at least one other conductor comprises more than one metal, covering at least the joint with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line system is configured to propagate the signal.

12. The transmission line system of claim 11, wherein if the at least one other conductor comprises at least one of more than the one metal, an adhesive, and the mechanical fastener, at least the joint is covered with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

13. The transmission line system of claim 11, wherein said at least one other conductor comprises only one metal that is silver.

14. The transmission line system of claim 11, wherein said one metal used to form said layer is silver.

15. The transmission line system of claim 11, wherein the transmission line trunk is configured to be coupled to at least one antenna; and is

Wherein each phasing line is configured to be coupled to a filter unit.

16. The transmission line system of claim 11, wherein the joint comprises one of a welded joint, a brazed joint, a welded joint, an adhesive joint, and a mechanical fastener joint.

17. The transmission line system of claim 11, wherein the conductor of the phasing line and the conductor of the transmission line trunk are each a center conductor of a coaxial transmission line.

18. The transmission line system of claim 17, further comprising at least one conductive portion forming an outer conductor of the coaxial transmission line.

19. The transmission line system of claim 18, further comprising at least one solid insulator interposed between the at least one conductive portion and at least one of the conductor of each phasing line and the conductor of the trunk transmission line.

20. The transmission line system of claim 18, further comprising at least one other conductive portion attached to the at least one conductive portion to form the outer conductor.

21. A remote antenna unit, comprising:

a first primary uplink signal path;

a first primary downlink signal path;

an nth primary uplink signal path, where N is an integer greater than or equal to two;

an nth primary downlink signal path;

a first duplexer coupled to the first primary uplink signal path and the first primary downlink signal path;

an Nth duplexer coupled to the Nth primary uplink signal path and the Nth primary downlink signal path;

wherein the first duplexer and the Nth duplexer are configured to be coupled to a transmission line system;

wherein the transmission line system comprises

A transmission line trunk connected to the first phase line and the Nth phase line;

If the at least one other conductor comprises more than one metal, the method further comprises covering at least the joint with a layer of one metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line system is configured to propagate the signal; and is

Wherein the transmission line system is configured to couple an antenna to the first duplexer and the Nth duplexer.

22. The remote antenna unit of claim 21, wherein if the at least one other conductor comprises at least one of more than the one metal, an adhesive, and the mechanical fastener, at least the joint is covered with a layer of one type of metal having a thickness equal to or greater than a skin depth corresponding to a carrier frequency of a signal, wherein the transmission line is configured to propagate the signal.

23. The remote antenna unit of claim 21, wherein the at least one other conductor comprises only one metal that is silver.

24. The remote antenna unit of claim 21, wherein the one metal used to form the layer is silver.

25. The remote antenna unit of claim 21, wherein the transmission line trunk is configured to be coupled to the at least one antenna; and is

Wherein each phasing line is configured to couple to a unique diplexer.

26. The remote antenna unit of claim 21, wherein the joint comprises one of a welded joint, a soldered joint, and a welded joint.

27. The remote antenna unit of claim 21, wherein the conductor of the phasing line and the conductor of the transmission line trunk are each a center conductor of a coaxial transmission line.

28. The remote antenna unit of claim 27, further comprising at least one conductive portion forming an outer conductor of the coaxial transmission line.

29. The remote antenna unit of claim 28, further comprising at least one solid insulator interposed between the at least one conductive portion and at least one of a conductor of each phasing line and a conductor of a trunk transmission line.

30. The remote antenna unit of claim 21, further comprising the transmission line system.

31. The remote antenna unit of claim 30, further comprising the antenna.